In their book, The Viral Video Manifesto, authors Stephen Voltz and Fritz Grobe lay out the core principles of creating a viral video and how to apply them. This edited excerpt explains what makes a video shareable -- the key to making it viral -- and why the techniques and tricks that make for great TV will, on the contrary, make for bad online video.

Most of what we all know about creating compelling video simply doesn't apply to viral video. Why not? Because what works in television does not work online.

Television is designed primarily to hook and hold viewers because, on television, as soon as the viewer flips the channel, the game is lost. So for 60 years, television has been getting better and better at keeping us from changing the channel.

The production and editing techniques developed for television -- quick cuts, multicamera shoots, odd camera angles, and the like -- do that beautifully. Television grabs us and keeps us watching for hours at a time so that, at the end of the day, even if we're drained and unsatisfied, television has done what it needs to do to be profitable: it has delivered our eyeballs to its advertisers.

But to go viral online, if all you do is hold our attention, you've failed. In viral video, your job isn't to keep viewers from changing the channel. It's to get them to love what you've made so much that they want to stop what they're doing and tell their friends. Viral video is about sharing. That makes it different from every other kind of moving picture ever made.

So how do you get people to share? You can't force it. But there are certain traits that viral videos have in common -- traits that help make them contagious. And that's something you can control. You can make a video with contagious qualities.

To get at what traits make these things contagious, let's look at sharing. Word of mouth has always been powerful, and the Internet has given everyone a megaphone. Whether you're on YouTube, Facebook, Twitter, Pinterest, or the next new social network, the way things spread is the same. Understanding the mechanisms of sharing will continue to be crucial to creating successful online content, whatever the next trend may be.

Sharing is about emotion: We're more likely to share something that makes us feel good; and we're more likely to share something that gets us fired up.

So negative emotions like sadness that make us passive, because when we're down, we don't want to share. Passive, positive emotions like contentment still don't stimulate sharing because, well, we're content. Negative emotions like anger and fear make us more active, so we're more likely to tell people about what's making us ticked off or afraid.

Best of all, however, are the things that are both exciting and positive -- the stuff that gets us saying, "That was hysterical!" To get people sharing, you need to get them actively engaged with strong, positive emotions. And here is where the attention-holding tricks of television actually work against you. While edits, pans, zooms, and sound effects will get and hold our attention, research has shown that these techniques make viewers more passive and distract them from the content itself.

Many exploit a primal human reaction known as the orienting response, which is a reflexive reaction triggered when we see a sudden movement or hear a sudden noise. It makes us immediately turn our attention to the source of the sound or movement. TV edits, pans, zooms, and sound effects also trigger our orienting response. Our brains immediately need to know, "What was that movement? What was that sound?" On television, these little reflex triggers are often coming at us several times per second, so our orienting response will not let us turn away.

Stimulating the orienting response like that has some side effects. Our heart rates slow. The alpha waves in our brains are blocked for a few seconds. In studies, TV viewers reported feeling relaxed and passive, and that passivity continued after they switched off the TV. But putting your audience in a passive mood is a problem when your goal is to get viewers to take the active step of telling their friends about what they've just seen. To go viral, you have to get your audience actively engaged.

Our involuntary "what was that?" reaction also depletes some of the mental resources we have available to process everything else we're taking in. In other words, the edits, the zooms, and the sound effects that draw our attention also slightly but significantly pull our attention away from the heart of your content and focus us instead on the attention-grabbing tricks. It distracts us from the actual content, making it more difficult to create an emotional connection.

There are four core principles to creating that emotional connection that leads to sharing and can help make your video contagious:
1. Be true.
2. Don't waste our time.
3. Be unforgettable.
4. Ultimately, it's all about humanity.

Stephen Voltz and Fritz Grobe

Stephen Voltz and Fritz Grobe are the founders of EepyBird LLC, a viral video studio based in Buckfield, Me., that created "The Extreme Diet Coke and Mentos Experiments," which garnered over 120 million YouTube viewers. They are the authors...